Rhabdomyolysis

Educational Objectives

The goal of this program is to improve management of rhabdomyolysis. After hearing and assimilating this program, the clinician will be better able to:

1. Recognize the causes and presentation of rhabdomyolysis.
2. Develop an appropriate plan for the management of rhabdomyolysis, regardless of cause.

Summary

Etiology: Black individuals, persons at extremes of age, and those with BMI >40 are at increased risk; rhabdomyolysis (RM) is a complex disease spectrum resulting from the breakdown of myocytes; may be precipitated by overexertion, drug intoxication, immobilization, crush injuries, electrical injuries, and temperature extremes

Indicators: a creatine kinase (CK) value ≥1000 U/L is consistent with RM; absence of ≈50% daily decline requires further evaluation; measurement of CK is the test of choice and the most sensitive indicator; CK has a half-life of 1.5 days; the level begins to rise within 2 to 12 hr, peaks within 1 to 3 days, and normalizes within 5 to 10 days; be appropriately aggressive with IV fluids; CK level does not correlate well with risk for acute kidney injury (AKI), except in the setting of a crush injury; in serious cases of RM with AKI, reported mortality rates are 4% to 20%; the short half-life of myoglobin and poor sensitivity for RM limit the utility of its measurement; mild RM (ie, CK levels 1000-5000 U/L) confers low risk for renal injury; likelihood for dialysis is increased with CK levels ≥15,000 U/L

Presentation: the classic triad (muscle weakness, myalgias, and dark urine) is observed in only ≈10% of cases; the most common presenting symptom is muscle aches; statins — ≈10% of patients taking statins report myalgias, but the risk of developing RM is very low; true statin myopathy is a genetic condition; RM with COVID-19 — presents with muscle aches and fatigue but not always with fever or the classic pulmonary symptoms; it should be considered in an individual who had normal renal function prior to infection and has since developed AKI; has been associated with use of hydroxychloroquine and oseltamivir to treat COVID-19

Laboratory tests: typically consist of electrolytes, liver function tests, urinalysis, and electrocardiography (ECG); hyponatremia, hyperkalemia, and hypocalcemia present early; later, myocyte death causes hypercalcemia; obtaining a coagulation profile is reasonable because the release of thromboxane can cause disseminated intravascular coagulation; ECG is reasonable in cases of AKI associated with RM; fluid administration corrects most electrolyte abnormalities

Drugs that cause RM: include statins, antipsychotic agents, steroids, selective serotonin reuptake inhibitors, propofol (seen with anesthesia or prolonged dosing), protease inhibitors, vancomycin, erythromycin, and baclofen; drugs of abuse — many are directly myotoxic; alcohol causes dehydration (inhibits antidiuretic hormone); the vasoconstrictive properties of sympathomimetic drugs (eg, cocaine, methamphetamine) can cause RM; these effects may be compounded by attempts to remove restraints

Overall management: identify the underlying cause, address temperature-related causes, control infections, and discontinue drugs that are directly nephrotoxic or cause decreased perfusion

McMahon score: a validated tool for prediction of renal dysfunction, renal failure, and mortality; it considers age, sex, initial creatinine level, electrolyte abnormalities, initial CK level (particularly if >40,000 U/L), and bicarbonate level; patients with McMahon score <6 and CK <5000 U/L can be hydrated but do not require aggressive measures; McMahon score ≥6 with a CK >5000 U/L indicates aggressive management; rehydration — the goal is to maintain urine output of approximately 250 to 300 mL/hr; fluid administration in oliguric or anuric patients can create volume overload; data support lactated Ringer’s (LR) or normal saline (NS) as reasonable choices with regard to clearance of CK or K, although switching to LR following the second liter of NS is recommended to avoid hyperchloremic metabolic acidosis; the early addition of bicarbonate may worsen hypocalcemia

BICAR-ICU trial (Jaber S et al [2018]): studied patients in the intensive care unit who were severely ill (ie, acidotic, with Acute Kidney Injury Network [AKIN] score ≥2 and Sequential Organ Failure Assessment [SOFA] score ≥4); the majority of patients were septic and/or required ventilation; the primary outcome was a composite of death from any cause at 1 mo and the presence of ≥1 organ failure at 1 wk; in patients with RM and AKI, a trend toward reduced risk for the primary outcome was observed among those who received bicarbonate; however, as there were many confounders, these results have not promoted a widespread change in practice

Role of diuretics and dialysis: mannitol — increases renal perfusion and decreases the formation of casts; studies reveal no benefit of mannitol or bicarbonate, compared with simple intravenous fluids; caution is advised if the patient is volume depleted; loop diuretics have no benefit, compared with fluid resuscitation; dialysis — required in 4% to 20% of patients with severe RM; continuous renal replacement therapy (CRRT) — removes myoglobin and inflammatory molecules; improves hemodynamics but (per a Cochrane review) does not reduce mortality; should be considered in patients with anuria or persistent hyperkalemia, hypercalcemia, or azotemia; CK level alone is not a good predictor of the need for CRRT

Readings

Cabral BMI, Edding SN, Portocarrero JP, et al. Rhabdomyolysis. Dis Mon. 2020; 66(8):101015. doi:10.1016/j.disamonth.2020.101015; Hohenegger M. Drug induced rhabdomyolysis. Curr Opin Pharmacol. 2012; 12(3):335-339. doi:10.1016/j.coph.2012.04.002; Huerta-Alardín AL, Varon J, Marik PE. Bench-to-bedside review: Rhabdomyolysis -- an overview for clinicians. Crit Care. 2005; 9(2):158-169. doi:10.1186/cc2978; Kamal F, Snook L, Saikumar JH. Rhabdomyolysis-associated acute kidney injury with normal creatine phosphokinase. Am J Med Sci. 2018; 355(1):84-87. doi:10.1016/j.amjms.2017.04.014; Lee GX and Duong DK. Rhabdomyolysis: evidence-based management in the emergency department. Emerg Med Pract. 2020; 22(12):1-20; Long B, Koyfman A, Gottlieb M. An evidence-based narrative review of the emergency department evaluation and management of rhabdomyolysis. Am J Emerg Med. 2019; 37(3):518-523. doi:10.1016/j.ajem.2018.12.061; Martin HA. Exertional rhabdomyolysis in the pediatric emergency department: A case review. J Emerg Nurs. 2016; 42(6):524-526. doi:10.1016/j.jen.2016.09.005; Nielsen FE, Cordtz JJ, Rasmussen TB, et al. The association between rhabdomyolysis, acute kidney injury, renal replacement therapy, and mortality. Clin Epidemiol. 2020 Sep 24; 12:989-995. doi:10.2147/CLEP.S254516; Safari S, Yousefifard M, Hashemi B, et al. The value of serum creatine kinase in predicting the risk of rhabdomyolysis-induced acute kidney injury: a systematic review and meta-analysis. Clin Exp Nephrol. 2016; 20(2):153-161. doi:10.1007/s10157-015-1204-1; Simpson JP, Taylor A, Sudhan N, et al. Rhabdomyolysis and acute kidney injury: creatine kinase as a prognostic marker and validation of the McMahon Score in a 10-year cohort: A retrospective observational evaluation. Eur J Anaesthesiol. 2016; 33(12):906-912. doi:10.1097/EJA.0000000000000490.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Weber was recorded at the 39th Annual Emergencies in Medicine Conference, held virtually March 7-12, 2021, and presented by Emergencies in Medicine. For information on upcoming CME activities from this presenter, please visit emergenciesinmedicine.org. Audio Digest thanks the speakers and presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

EM390502

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

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